Ultrasound-guided quadratus lumborum block with general anesthesia for perioperative circulatory stability in colorectal cancer surgery

Table 2 Variations in respiratory function indicators, mean ± SD

Time point	Indicators	Experiment group (n = 58)	Control group (n = 58)	t value	P value
T0	TV (mL)	500.25 ± 32.45	498.75 ± 30.62	0.256	0.798
T1	TV (mL)	480.50 ± 29.17	455.00 ± 30.75	4.582	< 0.001a
T2	TV (mL)	470.30 ± 28.92	430.40 ± 31.55	7.100	< 0.001a
T3	TV (mL)	485.75 ± 30.15	440.90 ± 29.80	8.057	< 0.001a
T4	TV (mL)	495.40 ± 31.25	465.50 ± 30.10	5.248	< 0.001a
T0	MV (L/minute)	6.25 ± 0.50	6.23 ± 0.48	0.220	0.826
T1	MV (L/minute)	5.90 ± 0.45	5.50 ± 0.55	4.287	< 0.001a
T2	MV (L/minute)	5.80 ± 0.50	5.20 ± 0.60	5.851	< 0.001a
T3	MV (L/minute)	6.00 ± 0.55	5.40 ± 0.65	5.367	< 0.001a
T4	MV (L/minute)	6.15 ± 0.52	5.80 ± 0.58	3.422	0.001a
T0	PaO2 (mmHg)	95.20 ± 5.80	94.90 ± 5.55	0.285	0.776
T1	PaO2 (mmHg)	90.15 ± 4.70	85.25 ± 5.20	5.324	< 0.001a
T2	PaO2 (mmHg)	88.00 ± 4.60	80.50 ± 5.10	8.317	< 0.001a
T3	PaO2 (mmHg)	90.00 ± 4.80	82.40 ± 4.85	8.482	< 0.001a
T4	PaO2 (mmHg)	93.50 ± 4.90	87.75 ± 5.00	6.255	< 0.001a
T0	PaCO2 (mmHg)	40.30 ± 2.80	40.20 ± 2.70	0.196	0.845
T1	PaCO2 (mmHg)	41.20 ± 2.60	43.00 ± 3.10	-3.388	0.001a
T2	PaCO2 (mmHg)	41.50 ± 2.75	44.20 ± 3.00	-5.053	< 0.001a
T3	PaCO2 (mmHg)	40.80 ± 2.90	43.80 ± 3.15	-5.336	< 0.001a
T4	PaCO2 (mmHg)	39.90 ± 2.50	42.50 ± 2.85	-5.223	< 0.001a

^aP < 0.05.

P indicating a statistically significant difference. TV: Tidal volume; MV: Minute ventilation volume; PaO₂: Partial pressure of oxygen; PaCO₂: Partial pressure of carbon dioxide.